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Documents and Collections

What is a document?​

  • A way to organize and store data as a set of field-value pairs
  • A document uses the JSON format
{
  "name": "Lakshmi",
  "title": "Team Lead",
  "age": 26
}
  • Internally MongoDB translates JSON to BSON (Binary JSON) to address shortcomings of JSON:
    • text based ⇒ space consuming
    • supports limited number of basic data types

JsonVsBson

The _id field​

  • Every document must have a unique _id value (unique in the collection it resides in)
  • ObjectId() us the default value for the _id field unless otherwise specified

What is a collection?​

  • An organized store of documents in MongoDB, usually with common fields between documents